The art of latch design is most assuredly a broad one. A host of patents exist which emphasize various attributes of a latch, whether structural or economical.
U.S. Pat. No. 4,322,958 by Eigemeier refers to a door lock with a spring bolt having a body molded from thermoplastic resin. Further the actuation mechanisms are molded from thermoplastic resins. Although such a structure may have an economical justification in some applications, not all uses would warrant the strength of locking portions exhibited by plastic and particularly for use in vehicles.
U.S. Pat. No. 4,130,308 by Jeavons refers to a motor vehicle door latch having a plastic molding located between front and back plates, the plastic molding for cooperation with a striker to guide it into engagement with the latch. Further an operating lever is molded from plastics materials. Such a mechanism does not however provide an integral structure which can be readily manufactured for quick assembly and precision of fit.
German Offenlegungsschrift 2,460,108 refers to a door lock wherein the components are manufactured from plastic with the exception of the key cylinder and fastening screws. The forces generated by the handle during opening are apparently resolved to avoid damage to the mechanism. However the latching parts do not appear to be strong enough to withstand the substantial loads encountered in vehicles. Further the latching parts are not remotely actuatable.
U.S. Pat. No. 4,538,845 by Yamada refers to a latch mechanism having a one piece molded plastic body having the latch and a release lever mounted thereon. The strength of the pivots for the latching portions would be questionable, without the addition of reinforcing plates, namely the addition of metal front and back plates and metallic actuating levers. Further the metal locking lever does not have specific parts defined within the molded body.
U.S. Pat. No. 3,876,283 by Waterman refers to what is purported to be a two part motor vehicle door latch. However when one reviews the patent one finds a pair of plates between which is sandwiched a molded synthetic-resin body which is attached to the outer plate and carries the locking pawl. Thus a plastic element of the latch is provided for elimination of rattles and squeaks and to provide general noise reduction in the lock. The inner plate carries the operating mechanism of the latch which is secured to the outer plate in assembly. Such assembly is not secured to a structural element of the vehicle. Further, it must be assembled while the door of the vehicle is being assembled.
U.S. Pat. No. 3,782,036 by Clark (referring to FIG. 7) describes a latch mechanism mounted on a reinforcing member. However the aforementioned reference does not provide for latching components which are secured to the structure but merely a lock bolt which passes through the securing flange.
U.S. Pat. No. 4,052,094 by Widen refers to a lock cassette secured to a recess in the end wall of a vehicle door. The lock is made of two main parts, a locking portion, and a control portion. The latch is embodied separately from the adjoining control portion.
Nowhere within the prior art is found an integrated latching mechanism for vehicles wherein the latching components are deliberately structured within a module of metal for strength and may be affixed to a metal reinforcing structural member of a door, and the actuation components are provided in modular form to integrate with the structural components and control the movement of the structural components. The use of plastic in latches for the majority of the prior art is limited in large extent to the damping qualities it brings to reduce noise and rattling. Nowhere within the prior art is found a latch housing module molded having actuation components molded and precisely guided within the compatible recesses found in the molded housing. The housing module also marries with the structural module quickly and efficiently to lend itself to assembly line technologies yet ending with an assembly which has all the advantages of a metal latch for strength and the economics of plastic molding techniques.
It is therefore an object of the invention to provide an integrated modular structural latch from metal in part and plastic in part as load characteristics dictate.
It is a further object of the invention to provide a latch mechanism that is economical yet safe and easily assembled.
It is a further object of the invention that the latch mechanism lends itself to assembly line technologies, yet is easy to maintain.
If is a further object of the invention to reduce the effect of winter conditions on a latch mechanism.
It is a further object of the invention to provide an integrated latch mechanism which will in use connect the forward and rearward pillars of the vehicle door.
Further and other object of the invention will be obvious to those skilled in the art when considering the following summary of the invention and the more detailed description of embodiments of the invention illustrated herein.